Seasonality of Pemba flying fox (Pteropus voeltzkowi) in selected habitats of Pemba Island, and its roles in seed dispersal and germination

Abstract

Understanding population variation in space and time can be used to enhance protection of keystone species. This study assessed Pteropus voeltzkowi seasonal use of four roosting sites characterised by three habitat types: Community conserved land (CCLH), Residential (RH) and Forest reserve (FRH). To provide information on their keystone role, the study recorded instances of seed dispersal and measured seed germination rate of two and four plant species respectively. A total of 88 roosting locations (18, 20 and 50 from CCLH, RH and FRH respectively) were studied. P. voeltzkowi abundance was estimated using patch counts conducted for four days in dry season (February) and four days in wet season (April). Transect and seed germination experiment were used to estimate seeds dispersal distances and germination rates respectively. The number of P. voeltzkowi was lower in the wet season and highest in RH. A positive relationship was found between P. voeltzkowi abundance and roosting tree canopy diameter. Fruits were dominant food item recorded, eighteen tree species were utilised as day roosts and fourteen were food source for P. voeltzkowi. Compared to unhandled seeds, handled seeds showed high germination rate. Maximum dispersal distances recorded were 560 and 200m for fig and mango seeds respectively.

Seasonal trends and population status of the highly threatened Pteropus livingstonii in the Comoros archipelago

“…On Comoros the hypothesized time of food scarcity is the dry season, which coincided with fewer bats present at roost sites. The seasonal fluctuations in flying fox distributions have been attributed to variation in feeding resources within a landscape [ 22 , 25 , 48 , 49 ]. While the feeding resources for this species are not fully identified, prior research points towards a dependence on native forest tree species [ 35 , 50 ].…”

“…While various active and passive monitoring methods exist [ 14 ], i.e., via camera traps, acoustic recorders, mark-recapture [ 15 ], tagging [ 16 ], direct point counts [ 17 ], transects [ 18 ], eDNA samples [ 19 ] or citizen science [ 20 ], there are considerable difficulties to consider when it comes to monitoring flying foxes as the animals are mobile, nocturnal, often roost in inaccessible areas, or the bats may be easily disturbed when approached [ 21 ]. Additionally, flying foxes show a pronounced response to seasonality across their range: Pteropus voeltzkowi density is lower during the rainy season [ 22 ] and both P. scapulatus and P. alecto move to satellite camps during periods of fruit abundance in the monsoon season [ 23 , 24 ]. Similarly, P. niger and several other species show differences in travelling distance [ 25 , 26 ] and population density of species visiting urban areas, such as P. dasymallus , also fluctuate across seasons [ 27 ].…”